Electric switch



April 9, 1929; H. v. HAIGHT ELECTRIC SWITCH Filed Dec. 17} 1925 IN If ENTOR. 1 17a: r

f fd TTRNEY Patented Apr. 9, 1929 UNITED STATES PATENT OFFICE.

HARRY V. HAIGHT, 0F SHERBROOKE, QUEBEC, CANADA, ASSIGNOR TO INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELECTRIC SWITCB Application filed December 17, 1925. Serial No. 76,045.

This invention relates to electric switches adapted to carry very heavycurrents, and its object is to extinguish the arcing at the switchcontacts in a simple and effective manner.

The switch of this invention is adapted to be pneumatically operated.The exhaust air utilized in operating the switch is arranged to blow outthe are between the switch contacts as they separate. In accordance withthe practice of this invention means is provided to which the are istransferred from the switch contacts, which is so constructed that thearc thereafter dissipates and extinguishes itself without causing injuryto the switch contacts.

Other objects and advantages of the inven tion will be in part obviousand in part pointed out hereinafter.

The invention will be more clearly understood by reference to thedrawings, in which similar reference characters refer to similar parts,and which include Figure 1, a front elevation of a switch constructed inaccordance with the practice of the invention; and

Figure 2, a vertical cross-section of the switch showing the switchoperating mechanism and more particularly the arc extinguishingapparatus.

Referring to the drawings, the switch includes two sets of relativelymovable electrodes, each comprising a stationary electrode A and amovable electrode B which are adapted to contact with each other tocomplete an electrical circuit. The contacts A are preferably rigidlymounted upon brackets C supported by insulating rods D extendingpreferably in a direction perpendicular to the contact faces of thecontacts A. The contacts B may be mounted pivotally upon plungers Eslidable within brackets F, also mounted on the rods D. Breaking of theelectrical circuit is accomplished by separation of the switch cont-actsA and B, which is effected by lowering the plunger E.

The brackets O and F may be constructed of metal to act as terminals forelectric cables G and H, whereby the current is supplied to the switchcontacts A and B. To provide a solid contact between the brackets F andthe contacts B flexible electrical conductors J may be bolted torearwardly extending portions K of the switch contacts B and at theother ends to the brackets F. The brackets C and F are adapted to carrycurrents and are each provided with arcing horns L and 0 re spectively,which diverge from each other from points adjacent the switch contacts Aand B. The arcing horns L and O are adapted to receive arcs transferredfrom the switch contacts A and B as the latter separate.

Due to the phenomena well known in the art,

an are between the arcing horns or electrodes L and O expands, and in adirection away from the switch contacts A and B, dissipating andextinguishing itself at the outer tips of the electrodes. The rods 1)are preferably mounted upon clamping brackets P and Q, in turn mountedon a panel or base R.

The relative movement of the switch contacts A and B is eficcted bymeans of a cylinder S, which may be formed integrally with the clampingbracket Q and provided with a piston T having a piston rod U extendingin the direct-ion of the switch contacts B. Each of the plungers E isprovided with a downwardly extending rod V connected with a cross headIV to which the piston rod U is bolted. The piston T is preferabiypneumatically operated, and to this end a. valve X is provided in a pipeline. Y leading to a source of compressed air or other suitable gas (notshown). In the base Z of the cylinder S there is provided a passage 6terminating in a valve seat 0. The base Z is provided with a cylindricalbore d in which a free floating piston valve 6 is adapted toreciprocate, having a groundseat f cooperating with the seat 0 to closethepassage b to the space above the pistin valve e. A bore 9 is providedlongitudinally through the valve 6 to admit compressed air from thechamber below the piston valve, through the passage 6, into the interiorof the cylinder S to force the piston T upwardly, to close the circuitof the switch contacts A and B. In its lowermost position the pistonvalve 6 seats upon a cap it closing the lower end of the cylindricalbore 03 to prevent the escape of air into the pipe line Y. In thisposition of the valve 6 exhaust motive fluid is permitted to escapethrough a passage j into a conduit is leading from the base Z of thecylinder S to a pair of nozzles 0 adjacent the the bore (Z of thecylinder base Z below the piston valve 6. The pressure of the enteringair forces the valve 0 upwardly, closing communication at the seat 0with the conduit Z2. Compressed air then passes through the bore y intothe cylinder ta, forcing the piston T upwardly and through the pistonrod U, closing the circuitthrough the contacts A and B and while theswitch contacts A and B are closed no air escapes from the supply lineY. \Vhen the contacts A and l) are open no air, except that previouslyentrapped in the cylinder S, which is used to blow out the arc, canescape for the valve X closed. It itis desired to break the circuitbetween the contacts A and B, the valve X is turned to the positionshown in Figure 2, whereat the supply of compressed air in the pipe Y isshut oil' and the pressure below the piston valve 6 is reduced bypermitting the air to escape through a port p in the valve X toatmosphere. This causes the piston valve 6 to drop, sealing itself uponthe cap it and preventing further escape of the air through the bore 9to atmosphere by way of the valve. X. The valve 6 being removed from theseat 0, compressed air can then escape from the interior of the cylinderS through the conduit and out at the nozzles 0 adjacent the switchcontacts A and B. Pressure in the cylinder S being released, the pistonT will drop by gravity and with the assistance of a compression springq, whereupon the switch contacts A and B separate. As is usual, an areforms between the switch contacts A and B but as the exhaustedcompressed air escapes from the nozzles 0 the arc is blown from theswitch contacts A and B to the stationary electrodes or arcing horns Land O. Substantially no burning of the switch contacts A and 15 occurs,due to the cooling action of the air and the short duration of the are.The are between the electrodes L and O dissipates and extinguishes itself because of the divergence of the opposed faces of the electrodes.

1 claim:

A switch comprising a rod, a pair of. brackets having arcing horns fixedon the rod, a switch contact rigidly mounted on one of said brackets, asecond contact movable with respect to said horn and guided by one ofsaid brackets to cooperate with the other contact, a nozzle directedbetween said contacts and toward said arcing horns, and pneumatic meansto actuate said movable contact member including a cylinder and pistonassociated with said movable contact member, a free floating valve forcontrolling the flow of mo tive fluid to said cylinder, and a conduitleading to said nozzle, said free floatingvalve being adapted to cutoil? communication between said motive fluid supply and said conduitwhile said switch is closed and to connect said cylinder with saidconduit when the supply of motive fluid for said cylinder is cut ofl.

In testimony whereof I have signed this specification.

HARRY V. HAIGHT.

